Spend my time here in NorCal where zebra mussels aren't a huge concern at my "home" lake. We are planning a trip to either pyramid or castaic lake with some SoCal family for camping/wakeboarding.

I guess I have two questions..considering I haven't been to the lakes down there which would be the best? Looking for a calm atmosphere for camping with a large toy hauler and hanging out with some family.....not a hard party weekend.

Second question is about the boat inspections I see on castaics site. They mention not one drop of water on your boat during inspection and we use sacs for ballast. Obviously we empty them after riding but even a complete empty leaves some water in the bags. Does this mean I would need to remove the sacs? I really hope not.

Remove your sacs! You will be denied! Also the most tricky thing they do is have you flip the bilge if one drop of water denied!they get slot of people on that make sure your exhaust ports are dry and your trailer tail lights have no water in them. Good luck

You'd best call the rangers there, it seems like the policy changes a bit each year, generally getting more stringent, but not always. We've had our boat in a number of So Cal lakes and it's always a huge deal trying to call ahead and figure out exactly what the inspection procedure is going to be and if we can pass-- our boat has hard ballast tanks, so removing isn't really an option.
We did not go to Castaic last year, but in the previous several years they didn't seem to worry about the ballast tanks, but they do open the engine cover and look in the bilge for any sign of water at all. Things (including toys, etc.) must all be completely dry.
We went to Piru last year instead, it has a more relaxed and mellow atmosphere than Castaic and we really enjoyed it. It has one arm of the lake where the kids can swim-- Castaic does not allow swimming in the main lake, only skiing. The inspection at Piru was probably even more rigorous than Castaic, but again for some reason the ballast tanks were not a concern.
Lake Nacimiento last year was the same story.
(I've read plenty of scary articles about having to bleach the ballasts or steam-blast with boiling water-- a procedure that requires an appointment ahead of time and some number of hours, but haven't actually run across it yet.) As I said this seems to be a bit of a moving target, so best to call ahead and find out for sure what the policy is this year as you don't want to arrive and be denied.

Very tough getting on castaic now days. I won't even bring my boat there, not worth the hassle. My buddy has his boat there and it is his home lake, when you leave, they can tag the boat for you putting a tag connect from your bow eyes to your trailer, so when you come back, if it is still there, you can launch. If the seal is gone, you go through the whole inspection again. Check your bilge, bags, ballasts tanks if you have them. My buddy was almost denied launch because his floor was wet due to spilling Ice when filling up the cooler.

Pyramid is pretty mellow, although I haven't been there in a few years. But I hear not much has changed.

They are all pretty terrible for getting good water. Are you planning a weekend or mid week trip? Last I remember the Castaic camp grounds are at the lower lake, so you are driving back and forth every day. I think Piru has a better camping situation, but the water is the lowest I have ever seen it there this year.

Have you thought about Buena Vista? Its just north of the Grapevine and you camp right on the water with your boat ready to go. A lot of the Bako locals do make it out there on the weekends, though.